[A.Hun]

Anytime you replace a package unit or the indoor unit of a central HVAC system, the ductwork has to be adapted to the new unit. We do it with new sheet metal plenums (boxes) that fit the new unit, then tie the existing duct back into the plenums.

All residential systems are based on 400cfm per ton of cooling, and that does not change from R22 systems to R410A systems.

THis entire changeover to R410A has been a total crock...the science concerning ozone depletion by R12 and R22 was bogus. It was simply a money maker for DuPont and Carrier in particular.

This particular situation is pretty weird...all new R22 units were phased out by 2008, and just this past winter were R22 outdoor units (shipped with no freon in them) allowed to be produced. THey changed the designation of the outdoor units from “system” to a “component”, allowing the manufacturers to make them again.

It is important because people are so broke, they can’t afford the additional couple of grand to change the indoor R22 coils to match an R410a outdoor unit. For most a/c units, it is a compressor failure that condemns the outdoor unit, and for years, you just installed a new outdoor unit of the same tonnage (some are not compatible, mostly based on differences on efficiencies from the old indoor coil being to small for the new 13 SEER outdoor units).

BTW, going from R22 to R410a cost mfgs about a 10% efficiency drop, forcing them to go to variable speed motorts, TXV valves, and larger coils to maintain the mandated 13 SEER efficiency.

[RicocheT]

I believe the newer refrigerant fluid is in all freezers and refrigerators as well as air conditions. My 40+ year old chest freezer out in the garage runs great in summer and in winter here in Wisconsin. I was told by an appliance dealer that the new refrigerators and freezers don’t work well out in an unheated space in cold as we have it in Wisconsin. Is that correct?

[dila813]

I don’t know, my pre-1965 house had to have new ductwork because there weren’t any returns to the furnance and the outlets were all in the hallways and the master bedrooms

I think the requirements for the ductwork for residential houses got updated in the 70s.

I still believe your average house is still pre-1980

[smokingfrog]

According to Honeywell, the new refrigerant is more efficient?

In less than 3 years the U.S. Department of Energy will require a 20% increase in the minimum efficiency of new home central air conditioners. This means that air conditioner manufacturers will have to find ways to increase the efficiency of their air conditioners. One easy way is to use a more efficient refrigerant, and because the refrigerant 410A is at least 5% more efficient than R-22, manufacturers can use R-410A to help them meet these energy efficiency goals.